show global status like 'Table_open_cache%'

shows output like:

# Variable_name, Value
Table_open_cache_hits, 749919
Table_open_cache_misses, 83398
Table_open_cache_overflows, 81276

 

If “Table_open_cache_overflows” is too high you must check

  • table_open_cache
  • open_files_limi

and set them higher. But it is not totally simple because there are limits on OS for maximum opened files (see “ulimit”)

Sources:

  1. http://techinfobest.com/optimize-mysql-table_open_cache/
  2. https://dev.mysql.com/doc/refman/5.7/en/table-cache.html